Dual wheel casters have over the past several decades achieved considerable commercial success for movably supporting office equipment and furniture. With the advent of high-strength plastics and design improvements it is now possible to support relatively heavy office equipment, such as copy machines and computer terminals on stands supported by all-plastic dual wheel casters at a cost far less than the cost of comparable metal casters.
Dual wheel casters have increased load capacity over single wheel casters, which in part enables them to be made from less expensive materials and an additional advantage of this caster design is that they swivel more readily than single wheel casters because the wheels can rotate in opposite directions as the caster pivots.
Plastic components used in constructing these dual wheel casters, are subject to scuffing during shipment when attached to office equipment and furniture, particularly in the wheel tread area. Frequently shipping personnel during loading and unloading at the delivery site will roll the equipment on the casters over abrasive surfaces such as asphalt and concrete, causing permanent wheel and horn member scuffing prior to the final delivery of the goods to the purchasing office location. It is possible to remove the csaters from the equipment and install the casters at the final office site, but this makes it considerably more difficult to move the equipment and it is therefore more desirable to have the casters in place during the delivery process.
One attempt at solving the problem is to surround the tread with an inexpensive plastic sleeve that is removed at the final destination. One such sleeve of which Applicant is aware includes an integral radial tab with a central finger hole that is pulled to remove it from the wheel when the caster reaches its final destination. The sleeve has several very thin radial projections around its inner edge that attempt to hold the sleeve axially in position on the associated wheel, but these projections frequently fail to prevent the sleeve from coming off during shipment resulting in dirty and damaged caster wheels. The narrow axial locking projections are necessary in this design in order to permit the removal of the sleeve at the final destination. Such a wheel protecting sleeve is manufactured by Steelcase Corp. of Grand Rapids, Mich.
It is a primary object of the present invention to ameliorate the problems noted above in protective devices for dual wheel casters.